Continuous train control system



June 13, 1933. w. D. HAILES 1,914,329

CONTINUOUS TRAIN CONTROL SYSTEM Filed Jan. 25, 1928 4 Sheets-Sheet l Flehl.

June 13, 1933. w. n. HAILES 1,914,329

CONTINUOUS TRAIN CONTROL SYSTEM Filed Jan. 25, 1928' 4Sheets-Sheet 2 Qukk Qelewpe Fiehz.

June 13, 1933. w HA|LE$ 1,914,329

CONTINUOUS TRAIN CONTROL SYSTEM Filed Jan. 25, 1928 4Sheets -Sheet 3 FIG.6.

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CONTINUOUS TRAIN CONTROL SYSTEM Filed Jan. 25, 1928 4 Sheets-Sheet 4 FIGA.

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' ATTCSRW Patented June 13, 1933 ETE ' WILLIAM. D. HAILES, LT ROCHESTER, IEEVJ YGBK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK CONTINUOUS TRAIN CONTROL SYSTEM Application filed January 25, 1928. Serial No. 249,457.

5 rect cur ent energy on the rails as distinguished from coded systems which employ alternating current energy on the rails.

In certain cases where a coded continuous type of train control system is desired, there may be no alternating current transmission line already in place, and hence, it alterna ing current is to be used on the rails, a Very considerable expense is incurred for erecting a transmission line, whereas, it a coded continuous system employing direct current rail energy be used, the necessity for a transmission line is obviated, in that the energy can be obtained from way side batteries, or the like.

Also. where a transmission line is in place, the track circuits can be normally fed with direct cur-rent from the trickle charge transmission line, and from battery in case 01 power failure.

h the above and other considerations V in mind it is proposed, in accordance with this invention, to provide a coded continuous train control system employing direct current e rgy on the rails. More specifically, the invention includes track way means for putting direct current onto the track rails and removing it therefrom in accordance with the particular code being employed, either directly so that direct current liows steadily during the on portion of the code, or a vibrating contact is utilized so as to give a nu ating direct current on the track rails during the on portion. It is furthermore proposed to apply the direct current in coded form to the track rails by means of first charging a condenser and then discharging the condenser across the rails, so as to provide several cycles of alternating current of diij rlshn amplitude for each condenser discharge.

Further, means are included on the car to end to the coded control current on the vck rails, and such means comprise a tuned receiving circuit which causes action of a tuned oscillating circuit to eXcite the grid of a. vacuum tube, together with circuits for energizing a primary coding relay so long as the said grid circuit continues to oscillate. Controlled by this coding relay are decoding ieans and secondary circuits for governing cab signals, brake actuating devices, and the lilre.

Further objects, purposes, and characteristic features will appear as the invention progresses, reference being had to the accompanying drawings showing, in a diagrammatic manner, and solely for the purpose of illustration, several forms of the invention. In the drawings:

Fig. 1 is a conventional view of trackway apparatus and a portion of car-carried apparatus, in accordance with this invention.

Fig. 2 is a conventional view of the remainder of the car-carried apparatus.

Fig.3 is a conventional showing of codes to be applied by the trackway apparatus of Fi 1, for the operation of the car-carried apparatus.

Fig. 4 is a. conventional view or a first modiiied form of trackway apparatus, including a vibrator in the coding circuit.

Fig. 5 is a conventional showing of a code as applied by trackway apparatus of Fig. 4, and of the resulting operation of part of the car-carried apparatus.

Fig. 6 is a conventional View of a second modified form of trackway apparatus, including a charging condenser and a transformer and connection thereof to the track rails.

Fig. 7 is a conventional View of a third modified form of trackway apparatus, including a charging condenser which is discharged by the interrupter directly into the rail circuit.

Fig. 8 is a conventional view of a code as applied by the forms of trackway apparatus of Figs. 6 and 7, and of the resulting operation of a part of the car-carried apparatus.

Traclcwwy apparatus J, by insulating joints 2, and provided with a wayside signal 3 at the entrance to each block.

It is to be understood that the present invention is wholly sufficient in itself, and can be used, if desired, without the wayside signals 3. These wayside signals have been shown, however, with a view to aiding the ready understanding of the trackway conditions represented, it being deemed unnecessary to show the usual circuits and devices for controlling and operating such wayside signals.

As shown, the blocks H and J are occupied by cars represented respectively by wheels and axles 4 and 5, thus making block J a danger block, block I a caution block, and block H a clear block, as regards the car 4.

The various devices and circuits associated with each signal location are identical for the several locations, and accordingl like parts are identified by the same re erence characters with distinctive exponents.

At each signal location is a track circuit battery 6, and code current battery 7 each connected throng a variable resistance, 8 and 9 respective across the track rails at the exit end of the block, and a track relay TR- connected across the rails at the entrance end to the block. Also at each location is a motor relay MR arranged to cut into operation a coding motor M, having vibrating coding fingers 10 and 11, respectively, for applying the clear or green code, G, and the caution or yellow code, Y, to the track rails, in accordance with traffic conditions ahead, as selected for example by relay TR.

The trackway apparatus employed in this invention is very similar to that employed in Patent No. 1,852,409 dated April 5, 1932, and copending application Ser. No. 228,059 filed October 22, 1927.

Each track relay TB is normally energized by current from its track battery 6, through a circuit which includes a contact finger 13 and back point of relay MB at the control position ahead, and which relay is controlled, in turn, by the track relay TR fed by such current from battery 6. The coding motor M is energized through a con tact finger 12 and front point of the associated motor relay MR, while the coding current battery 7 is connected across the track rails through a contact finger 14 and front point of such relay lWR.

Considering the showing in Fig. 1 of the trackway apparatus, it will be seen that each coding motor M is normally de-energized by the retraction of contact finger 12 of its associated motor relay MR, and is energized only when such relay MB is energized.

Each motor relay MR is energized through contact finger 130, and back point of the track relay at the entrance to the block in question. Accordingly, upon occupancy of a given block, as I, its track relay TR is dropped which thus picks up the motor relay MR which controls the code motor M for placing coded current on the rails of the said occupied block I. On pick up of the relay MR, its finger 13 disconnects track circuit battery 6 from the track rails, while its finger 14 connects a coding current battery 7 across the rails in its stead, through a circuit including, one rail, resistance 9, contact finger l4 and front point of MR, one of code fingers 10, 11 of M, in the closed position, contact finger 15 and front or back point respectively, of relay TR, to the other track rail. With the motor M vibrating its code fingers 10 and 11, current from battery 7 is applied to the track rails, and removed therefrom, in accordance with the particular code finger 10 or 11 which has been selected by contact finger 15 of track relay TR, so that coding current is applied to the track rails, and removed therefrom, in accordance with the particular code selected.

It will be noted in Fig. 1, that block H is being supplied with the Gr or clear code, through code finger 10 and contact finger 15 and front contact of track relay TR of block I. Since block H is occupied, its track relay TR (not shown) is tie-energized, to thus energize relay MR to thereby energize motor M for applying the coded current to block H, and at the same time remove battery 6 from across the track rails of block H and apply battery 7 across the track rails through the active code finger 10 and contact finger 15 of track relay TR.

Considering now block I, since this block is not occupied, its track relay TR is energized to thus de-energize relay MR positioned at the exit end of such block. This deenergizes code motor M and cuts off code battery 7 from the exit end of block I, and ap plies track battery 6 across the exit end of such block I.

The track relay TR for block J, is de-energized, since the block is occupied, to there by drop its contact finger 15, so as to select code finger 11 for applying the Y, or caution code, to block I, as soon as such block is occupied.

In block J, of course, due to the shunting effect of the axle and wheels 5, no current is present on the track rails in this block to the rear of car 5, and hence this portion of trackway becomes a danger or stop territory, and will cause an R indication on a following train.

The trackway apparatus described above thus operates to apply coded direct current to the track rails in accordance with traffic conditions and track hazard ahead, in a particular manner, as, for example, as shown in Fig. 3, for the G code and Y code. As seen from Fig. 3, the G or clear code comprises a succession of evenly spaced on and off periods of control direct current (shown as spaced .2 seconds). The caution or Y code comprises a succession of extended on and off periods of control current (shown as spaced 2.8 seconds). Danger or R conditions are normally accompanied by no control current at all, but if, for any reason, it should be accompanied by the control current steady on, the car-carried apparatus to be described will still operate satisfactorily.

Oar-carried apparatus Cooperating with the trackway apparatus described above, is car-carried apparatus as illustrated partly in Fig. 1, and the remainder in Fig. 2.

Carried by the locomotive, in advance of its foremost axle and pair of wheels, are receiving coils 16, positioned above the track rails in inductive relation thereto, so as to be inductively affected by the coded control currents flowing along one track rail, through the wheels and axles of the train, and back through the other track rail. These coils 16 are so connected as to have the voltages induced therein by the rail current, cumulative. The receiving coils 16 are connected in areceiving circuit 17 which includes a tunlng V condenser 18 and the primary of a transformer T. This receiving circuit 17 is tuned to oscillate most freely at a frequency preferably different from commercial frequencies, such, for example, as 100 cycles per second.

The receiving circuit 17 on the car supplies energy to the input end of an amplifying means designated as a whole by AD, while the output end of AD supplies pul- 4 sating energy to a coding primary relay The plates are included in plate circuits which are fed from a plate battery 29. The plate circuit for plate 26 includes in series therewith a reactance 31, and the plate circuit for plate 25 includes a reactance 32, and also a feed back coil FB for feeding energy back from the plate circuit of tube 19 to the grid circuit of such tube.

Across the secondary of transformer T which forms the grid circuit for grid 23 of tube 19 is connected a condenser 33, which is adjusted so that said grid circuit oscillates most fully at 100 cycles per second. An auto-transformer 34 is provided, having its primary 35 connected thru condenser 37 across tube 19, while its secondary is connected in series with grid 24 of tube 20. The

coding relay CPR is connected, in series with a condenser 36, and across the reactance 31 of the plate circuit of the second tube 20.

The condenser 33 tunes the grid circuit for tube 19 to oscillate most freely at a frequency of 100 cycles per second. A condenser 37 is connected in series with the primary of auto-transformer 34: and acts as a blocking condenser to prevent direct current from flowing in this circuit. Condenser 38 is connected across a portion of the secondary of transformer 3 1 for tuning the circuit of grid 24 for resonance at 100 cycles per second. In a like manner condenser 36 in series with relay CPR tunes the relay energizing circuit for resonance at 100 cycles per second.

l Vith the apparatus described above, a change of flux passing through receiving coils 16, produced by a change in current fiow in the track rails, causes an induced current to flow in the tuned receiving circuit 17. This in turn causes a current to flow in the secondary of transformer T and condenser 33, and since this circuit is tuned such current will oscillate, first in one direction and then in the other, for a short period of time before dying away and these oscillations will be sustained to a desired extent if necessary by adjustment of the feed back coil FB. Due to this oscillating current the grid 23 of tube 19 will be excited by several cycles of alternating current, before the oscillations in the receiving system and grid circuits die away. During this time the amplifier will respond to the excitation on grid 23 of tube 19 and in turn excite relay CPR, and cause it to attract its armature and hold its armature until the oscillations have decreased to a point at which the amplifier output can no longer hold the armature attracted.

Considering the operation of the ampli fier somewhat more in detail, the oscillating current in the secondary of transformer T will vary the potential on grid 23 of tube 19, whereby pulsating direct current will flow through the circuit of plate 25 of this tube. The primary 35, of transformer 34, connected across tube 19, will have an alternating current flow through it and the condenser 37 in series with it, so that the secondary of this transformer 34 will apply an alternating voltage to grid 2% of the sec ond tube 20, to thus cause the current flowing in the plate circuit of this tube to be a pulsating direct current. This pulsating direct current in the plate circuit of tube 20 can be considered to separate into its direct current and alternating current components, the first flowing mainly through reactance 31, plate 26, etc, and the second. the alternating current, through relay CPR .and condenser 36. i

It is thus seen that the net effect of the apparatus so far described, is to cause energizing current to be applied to relay CPR,

upon a change'of currentfiow in the track rails, and by adjusting the various parts of the device AD, and including the feed back coil FB, this energy can be made to flow a sufiicient length of time to pick up the relay. That is, by shock exciting the receiving circuit on the car by coded direct current, a coding primary relay CPR, is energized, to first pick up and then release. Relay CPR could,

. of course, be of any desired direct current type, and operate satisfactorily by merely inserting a rectifier in series therewith in its energizing circuit.

Considering for a moment the set of codes shown in Fig. 3, it will be seen that the clear code consists of first applying direct current to the track rails, then removing it, then reapplying it, etc., whereas the caution code comprises first applying direct current to the tract rails and not again removing it until an extended interval of time and then again applying it after a second extended interval of time. Each time the direct current is applied to the track rails, the current builds up change of flux threading the receiving coils 16, and thereby shock excite the input circuit of the device AD. Likewise, on each removal of direct current from the track rails, change in flux through the receiving coils 16 occurs, with a like effect on the device AD.

As indicated graphically in Fig. 3, upon each shock excitation of the receiving means on the car energy is applied to relay CPR, and

is maintained in turn to a value above the pick up value for the relay, a sufficient time to pick up the relay, after which the applied energy dies down and in the meantime the relay releases. Thus the relay picks up and releases once for each application of control current to the track rails, and once for each removal of control current from the track rails.

Referring now to Fig. 2. of the drawings, the remaining portion of the car-carried apparatus will be described. Inasmuch, however, as the apparatus shown in Fig. 2 is substantially the same as shown and described, in considerable detail, in applicants co-pending application Ser. No. 228,059 filed October 22, 1927, it is deemed unnecessary to do more than very cursorily consider the construction and operation of this portion of the carcarried apparatus.

As stated, this apparatus is practically identical with that in the referred to application, except that, in the present case, it has been simplified by having it arranged for three indications only, rather than for four, as in the prior application, that is, for clear, caution and danger only, the indication, approach restricting Y/G, being omitted from the present case.

Shown in Fig. 2 are the receiving coils 16 connected to the input side of the device AD, which is shown diagrammatically by a rectangle, while the output side of such device is connected to relay CPR, as described in connection with Fig. 1.

Controlled in accordance with the operation of relay CPR is a decoding means comprising relays R R R and R repeater relays R Rep, Y Rep, and G Rep, corresponding respectively to the cab signals R, Y and G; two stick relays R Stlc and Y Stlc, corresponding respectively to the relays R Rep and Y Rep; a device EPV which, when de-energized, applies the brakes or imposes any other desired train movement restricting effect; a relay EPVR controlling the energizing circuit for the device EPV; an acknowledging device A070; and an audible whistle valve signal AWV.

All of the relays referred to above in connection with the car-carried apparatus shown in Fig. 2, are relatively quick to pick up, but certain of them are slow to release, and the various release times for the different relays have been indicated on the drawings in a manner similar to that in applicants co-pending application Ser. 1 0. 228,059.

The various parts have been shown in Fig. 2 in the normal positions, that is, the positions assumed under clear conditions. It will be seen on inspection that the whistle valve AWV is de-energized, that the cab signal G is energized, that a brake application is held off by the energization of EPV, and that relay Cr Rep is energized while the other two repeater relays are deenergized. Under such clear conditions all of the relays R R are up, so that relay G Rep is energizcd each time the coding relay CPR releases.

It will now be considered, very briefly, what occurs when conditions change from clear to caution, any more detailed desired description being obtainable from the referred to copending application Ser. No, 228,059. Upon experiencing either the first on or the first off portion of the Y code, relay CPR first picks up and then releases in the same manner as for the G code, but since a second change in current flowing in the track rails does not at once occur as with the G code, (but there is a wait of 2.8 seconds according to Fig. 3) relay CPR stays down and shortly thereafter, in accordance with the various release times indicated therefore, decoding relays R R all released. This results in a de-energization of relay G Rep as soon as relay R releases, so that five seconds thereafter relay G Rep releases.

Prior to the release of relay G Rep, how ever, a change in the track current has occurred in accordance with the Y code as shown in Fig. 3, so as to cause relay CPR to pick up once and then release once. On the first pick-up of CPR, R and R pick up; on the following release of CPR, R picks up and then sticks up. The next pick-up of CPR occurs long enough later to have allowed R R and R to have released. This results in pick up of decoding relays R -R ut leaves relay down, thereby to ut energy on relay Y Rep as soon as de-coc ing relay R releases.

With relay Y Rep picked up, as soon as relay G Rep releases the cab signal indication changes from to Y, and also the de vice AWV gives an audible signal as additional warning to the engineer that traific conditions have changed to more restrictive, and that acknowledgment is necessary. At the same time that the cab signal changes and AWVV is sounded, relay EPV-R is de energized by release of relay G Rep, but does not immediately release to thus de-energize EPV and apply the brakes, since its dropaway time is, for example, five seconds.

Assuming that the engineer acknowledges, he depresses the device A0176 to thereby put energy on relay R Silo which, on being picked up, puts energy on relay Y Stir, which latter when once picked up is stuck up through a front point of relay Y Rep. lVith relay Y S670 up, an energizing circuit is completed for relay EPV-R which includes a front point of this stick relay, and thereby de-energization of EPV is forestalled. Actuation of the acknowledging contactor A070 must be effected before release of relay EPVR in order to be effective. Of course, on pick up of the relay Y S2572, AWV is silenced, thus advising the engineer that the acknowledging contactor can safely be released.

The cab signal, as referred to above, changes from G to Y upon release of relay R Rep, through the various energizing circuits for these signals, in the same manner as described in detail in applicants co-pending application Ser. No. 228,059.

As described in the above referred to copend n appication, if there is a failure to acknowledge within the proper time, upon a chan e intraffic to more restrictive conditions, the device EPV is de-energized, a brake application is incurred, and to restore the parts so as to release the brakes, the device lies must be operated, and since this is actuable only from the ground, the train must first be brought to a full stop. Operation of Res puts energy on relay R Si k in the same manner as does the timely operation of A070, so that the subsequent operation of the various parts occurs in the manner described above when acknowledgment was properly performed.

The above description of applicants invention, makes clear that coded direct current, placed upon the track rails, can operate to shock excite car-carried apparatus to cause operation of a coding primary relay CPR, in a selected manner in accordance with the track code in question. It is also clear that the selected operation of relay CPR, controls a decoding means which sets up secondary circuits for energizing cab signals, giving an audible signal, and enforcing timely acknowledging; or subsequent resetting.

This invention however noes not contemplate any particular form of code, or any particular form of decoding device and secondary circuits, and it is obvious that these I can be modified and varied in accordance with conditions to be satisfied. For example, the form of decoding means shown in Fig. 2 is substantially identical with the first form of decoding means shown in application Ser. No. 228,059. This has been shown merely by way of example, however, and it is to be clearly understood that a modified form such as shown in Fig. 6 of such co-pending application could equally well be employed.

Likewise as regards the codes shown in Fig. 3, these are given merely by way of example, and correspond generally with the first form of code shown in application Ser. No. 228,059. However, the other three forms of codes shown in such application, namely in Figs. 7, 9 and 11, could equally well be employed in the present invention.

Reference was made above to applicants Patent No. 1,852,409 dated April 5, 1932, and it is further contemplated that the decoding means and secondary circuits shown in such case could equally well be employed in the present application, and as well, likewise, the codes shown in such application.

The particular codes selected, and the particular de-coding and secondary circuit means selected for illustration in the present case, for the'purpose of constituting a complete disclosure, have been shown merely by way of example, and obviously other codes, including such as shown in applicants former applications referred to above, and other decoding and secondary circuit means, also including such as shown in such former applications, can equally well be employed in the present case.

Modifications imparted to the receiving coils 16 on the car and carried on to the device AD.

As in connection with Fig. 1, upon a train entering block H for example, under clear trafiic conditions, its track relay, not shown in Fig. l, releases, to thereby pick up relay MR Picking up of relay MR cuts off track circuit energy supplied by track battery 6 closes the energizing circuit for the coding motor CBP, and applied the control current battery 7 across the rails through a circuit which can be traced as follows :One of the track rails, variable resistance 9 battery 7 contact finger 12 and front contact of relay MR vibrating contact 39 and front contact of a vibrator 40, coding finger 10 of the coding motor CM contact finger l and front contact of relay TR, to the other track rail: The vibrator 40 is, as shown, connected to be energized from battery 7 upon picking up of relay MR through an energizing circuit including one terminal of the battery 7, contact finger 12 and front contact of relay MR contact 41 and back point of vibrator 40, the windings of vibrator 40, and back to the other terminal of battery 7 The only chan e from the form shown in Fig. 1 and described above, resides in inserting a vibrating contact in the code applying circuit, with means for starting the contact to vibrating at the same time that the coding motor is cut into operation. Obviously this general result can be obtained in other manners, such for example, as having the usual cams of the coding motor which operate the .coding fingers and 11 supplied with a series of teeth on the coding portions so as to cause the coding fingers themselves to vibrate. Or, a separate single cam, having fine teeth around its entire periphery, can

be operated by the coding motor, and actuate a contact finger connected in series with each one of the coding fingers, whereby to avoid changing the design of each separate coding finger and cam. Y

The result obtained by the modified form of apparatus shown in Fig. 4, and just described, is graphically illustrated in Fig. 5, in which it is seen that the clear or G code differ from that shown in Fig. 3, by having each on period of current consist of a rapidly pulsating direct current, rather than a steady current. Instead, therefore of shock exciting the receiving apparatus but once for each code impulse, it is shock excited a number of times, whereby the energy placed on relay CPR. instead of gradually dying away after the first shock excitation, is maintained substantially at its maximum value until the code impulse is over. In this manner the relay CPR can be energized a suflicient length of time with current of pickup value, while psing less energy on the track rails, than with the single shock excitation, and this is due to the fact that, with the form of ap paratus of Fig. 4, the receiving means is successively shock excited so as to maintain the value of current in the CPR relay circuit substantiall at its maximum value throughout the code impulse, so that the maximum value need only just exceed the pick up value of current for the relay CPR.

Considering Fig. 3 however, it is apparent that, with tracliway apparatus as shown in Fig. l, for each application and each removal of current from the track rails, single shock excitation is imparted to the receiving apparatus on the car. This results in oscillations which rapidly diminish in amplitude, whereby it is necessary to shock excite the apparatus so forcibly as to give an initial current value on the relay CPR enough grea. er than its pick up value, to insure pick up value current continuing on the relay long I enough to certainly pick it up before the oscillations die down to a point corresponding to less than the pick up value of current for such relay CPR.

It should be noted that with the apparatus as shown in Fig. 4, each application of code current to the track rails produces a series of shock excitations in the receiving apparatus which results in the coding primary relay CPR picking up once and releasing once. In the form of apparatus of Fig. 1, however, this same relay CPR picks up and releases twice for each on period of current, that is, for each application, and each removal, of current to and from the track rails. Accordingly, for the same effect to be produced on the relay CPR, the coding motor, when applying coded current by means of apparatus as shown in F 4, must operate its coding fingers at just twice the rate required when coded current is put on the track rails by means of apparatus as shown in Fig. 1.

Referring now to Fig. 6, there is here shown a second modified form of trackway apparatus for applying coded direct current energy to the track rails. In this form, instead of connecting the rails direct with the control current battery 7 the circuits are so arranged that in one position of the coding fingers, this battery is connected across a charging condenser 40, and in the other position of the coding fingers, this condenser is connected across the primary of a transformer 41. The secondary of transformer 41 is connected across the track rails in series with a condenser 42 for tuning the track circuit to oscillate, for example, at 100 cycles per second. A track battery 43 is connected across the rails in series with alimiting resistance 44 and a reactance 45, whereby to enable the coded oscillating control current supplied to the track rails by the condenser to create an inter-rail potential, and thus cause a flow of control current down one rail and back through the other. In a manner similar to the previously described two forms of trackway apparatus, the track relay TR selectively connects the proper code finger into the coding circuit for block H by means of its contact finger 15 while the contact finger 13 of this relay controls the energizafor the apparatus of l? tion of the code motor (rot shown) for the lock 1 Considering the parts in the various positions shown in 6, and assuming that a train enters bloclr H this will cause release of the traclr relay at the entrance end of block E to thereby pick up relay lilll to in turn energize the coding motor CM which immediately starts oscillating the coding fingers 10 and 11 Block H being a clear lJlOClZ, will receive code through code finger 1.1 which has been sel cted by contact finger 15 of track relay T3 in attracted position. With code finger 11 down, charging condenser i0 is connected across the terminals of battery 7 a circuit including; condenser 40, contact finger 15 and front point of track relay T11 coding finger 111 and back point of the coding motor Gi /l the battery 7 and back to condenser 40. As soon as the coding finger 11 is moved to its upper position, the now charged condenser 40 is placed across the primary of transformer all through a circuit including; condenser 40, contact fine'er 15 and front point of the track relay T3 coding finger 11 and front point of coding motor Ch l a contact finger and front point of MR the primary of transformer ll, and back to condenser lO. The condenser 40 thus discharges through the primary of the transformer, then is recharged in the opposite direction, and so on, to cause an oscillating current to periodically flow in the secondary of the transformer ll and the traclr rails, these oscillations gradually diminishing'in amplitude. The circuit just described, including the charging condense 40 and the primary of transformer ll, is tui ed to oscillate at cycles per second. In this manner, on each complete up and down motion of the coding fingers the charged condenser is connected, discharges, across the track rails by means of the transformer ll.

The current produced in the track rails in accordance with Fig. 6. is graphically represented in fi 8. Each time the charged condenser is applied to the track rails, the receiving on the car is shock orcited a plurality of times in rapid succession, to a success rely diminishing degree, and the energy appiied to relay CPR is somewhatas represented in 8. Thus, for each application of the char ed condenser, relay CPR picks up and releases. i iccordingly, as

q'. 5h ere is one pick up of relay CPR. and o release. for each tc up and down movement of the cods, instead of complete pick up of relay CPR for each complete ment of the coding finger ,paratus shown in and rcieases 1 ano down move as is the case of the a 1% 1.

Referring now to Fi 7, there is here shown a third modified form of apparatus for applying coded direct current energy to the track rails. This form is very similar to that described in connection with Fig. 6, the only difference being that no transformer is employed, but the charging condenser d6 is connected directly across the track rails, it havin previously been charged by being connected across the control current battery 7 The same arrangement is here employed as used in the Fig. 6 form, for the track battery a7, and the resistance and inductance 4:8 and 4:9 in series therewith. In this form, the condenser 46 is arranged to tune the track circuit for oscillation at 100 cycles per second.

No more detailed explana ion of the operation of this form should be necessary, in view of the description of the similar form of Fig. 6, set forth above. Accordingly, merely the charging circuit for condenser 46 will be traced, and likewise the discharge circuit for this condenser across the track rai s. l Vith coding finger 11 of the code motor in its retracted position, condenser 46 is connected across charging battery 7 by a circuit includ ing; condenser 46, contact finger l5 and front point of track relay T3 codin finger 11 in its lower position, charging battery 7 and back to condenser ll-(i. lVith the coding tinge ll in its raised position, as represented '11 I ig. 7, the charged condenser l? is placed ir ctly across the traclr rails by a circuit in- Cillfilllg; one of the track rails, condenser contact finger 15 and front point of track TR coding linger 11 in its raised position, a contact finger and front point of MR the other track rail, and back through car wheels and axles to the first rail.

In the form shown in Fig. 7, it will be seen that the operation, and effect, on the car-carrier ap aratus is substantially the same as with that of Fig, 6, and accordingly the graphic representation of Fig. 8 applies equally to this form of 7 and to the form of Fig. 6. Likewise, as with Fig. 6, each complete up and down movement of the coding fingers causes the coding relay CPR to pick up once and release once.

The above description of applicants invention has been given primarily with a view to simplifying a complete understanding of the invention, rather than with any idea of showing the apparatus and the arrangement thereof, as would preferably be employed i actual receivin means res )onsive to said coded current and connected to shock excite said oseillating circuit, decoding means energized only during oscillation of said oscillating circuit, the decoding means changing its operation position for each separate current impulse and control and indicating means selectively controlled by said decoding means.

2. In a coded continuous train control sys tem, in combination, trackway means controlled by trafiic conditions ahead for applying coded direct current to the track, carcarried means inc uding an oscillating circuit and an audion tube means controlled by said oscillating circuit, a receiving means responsive to said coded current and connected to shock excite said oscillating circuit, feed back means to sustain said circuit in oscillation for a time, a decoding relay energized only during oscillation of said oscillating circuit,

and control and indicating means selectively ,1, relay.

3. In a coded continuous train control system, trackway means for applying coded direct current to the trackway for train control, car-carried receiving and decoding means distinctively and continuously responsive to the presence of said control current, and including, receiving coils positioned to be influenced by the control current, an os cillating circuit arranged to be shock excited by said coils to be set into oscillation, audion tube means having its input side controlled by said oscillatory circuit, a decoding relay connected to the output side oi. said tube means, means whereby energy is supplied to said relay only while said oscillatory circuit is oscillating, and means controlled by said relay.

4. In a coded continuous train control system, trackway means for applying coded direct train control energy to the trackway, car-carried receiving and decoding means distinctively and continuously responsive to the presence of said control current, and includcontrolled by said decodin 1ng, receiving coils positioned to be influenced by the control current, an oscillating circuit tuned for a noncommercial frequency and arranged to be shock excited by said coils to be set into oscillation, audion tube means having its input side controlled by said oscillatory circuit, a feed back means for helping to sustain oscillations in said circuit, a decoding relay connected to the output side of said tube means, means whereby energy is supplied to said relay only while said oscilla- 1 tory circuit is oscillating, and means controlled by said relay.

5. In a coded continuous train control system, trackway means for applying coded direct current energy to the trackway in accordance with trafiic conditions ahead, carcarried circuits, and car-carried receiving and decoding means arranged to selectively control said circuits, and comprising, receiving coils inductively related to said coded current, an oscillatory circuit controlled by said coils, a first audion tube connected to have its output current modulated by said oscillatory circuit, a feed back coil for said oscillatory circuit connected in the output side of said tube, a second tube connected to have its output current modulated by said first tube, and a coding relay connected in the output circuit of said second tube in series with a blocking condenser, whereby only alternating current flows in said relay only so long as said oscillatory circuit continues in oscillation.

6. In a coded continuous train control system, trackway means for applying coded direct current energy to the trackway in accordance with tratfic conditions ahead, carcarried controlled circuits, and car-carried receiving and decoding means, arranged to selectively control said controlled circuits, and comprising, receiving coils inductively related to said coded current, an oscillatory circuit controlled by said coils, an audion tube device connected to have its output current modulated by oscillations in said oscillatory circuit, feed back means for feeding energy from said tube device to said circuit to maintain oscillation in said circuit, and a coding relay connected, in series with a blocking condenser, to be energized by the output current of said tube device, whereby energization of said relay depends on oscillations in said oscillatory circuit.

7. In a coded continuous train control system, in combination, trackway means including normally energized track circuits, means for applying coded direct current to the track rails in accordance with traflic conditions ahead, and traiiic controlled means for deenergizing said track circuits during application of coded direct current to such track rails, car-carried receiving and decoding means continuously responsive to the presence of coded current, a vibrator having a vibrating contact included in the circuit for applying coded direct current to the track rails, means for energizing said vibrator only during application of coded current to the track rails and circuits selectively controlled by said receiving and decoding means.

8. In a coded continuous train control system, in combination, a stretch of track divided into insulated blocks, a normally energized track circuit for each block, means for selectively applying coded direct current to each block in accordance with traffic conditions ahead, trafiic controlled means for simultaneously taking track circuit energy off of the rails and putting coded direct current onto the rails, car-carried receiving and decoding means continuously responsive to the presence of coded current, a vibrator having a vibrating contact included in the circuit for applying coded direct current to the track rails, means for energizing the vibrator only during application of coded current to the track rails, and circuits selectively controlled by said receiving and decoding means.

9. In a coded continuous train control system, in combination, a stretch of track divided into insulated blocks, a track circuit battery connected across the rails of each block in series with an inductance, means for selectively applying coded direct current to the track rails in accordance with trafiic conditions including a coder, a source of direct current, and a condenser, so connected that the condenser is alternately connected to be charged by said direct current source and then to discharge to put coded energy onto the track rails, while the coder is operating, car-carried receiving and decoding means continuously responsive to the presence of coded current, and circuits selectively controlled by said receiving and decoding means.

10. In a coded continuous train control system, in combination, a stretch of track, divided into insulated blocks, a track circuit battery connected across the rails of each block in series with an inductance, means for selectively applying coded direct current to the track rails in accordance with traiiic conditions including, a coder, a source of direct current, a track transformer, and a condenser, so connected that the condenser is alternately connected to be charged by said direct current source and then to discharge through the primary of said track transformer to thus put coded energy onto the track rails, car-carried receiving and decoding means continuously responsive to the presence of coded current, and circuits selectively controlled by said receiving and decoding means.

11. In a coded continuous train control system, in combination, a stretch of track divided into insulated blocks, a track circuit battery connected across the rails of each block in series with an inductance, means for selectively applying coded direct current to the track rails in accordance with traflic conditions including, a coder motor, a direct current source of control current, and a condenser, so connected that operation of the coder motor alternately connects the condenser across said direct current source to charge it and directly across the track rails to discharge it and apply control current to the rails, car-carried receiving and decoding means continuously responsive to the presence of said coded current, and circuits selectively controlled by said receiving and de coding means.

12. In a coded continuous train control system, in combination, trackway means controlled by traiiic conditions ahead for applying coded direct current, comprising relatively' widely separated current impulses, to the traclrway, car-carried means including an oscillating circuit and an audion tube means controlled by said oscillating circuit, and receiving means responsive to said coded current and connected to shock excite said oscillating circuit.

18. In a coded continuous train control system, in combination, trackway means controlled by traflic conditions ahead for applying ceded direct current, comprising relatively widely separated current impulses, to the trackway, carcarried means including an oscillating circuit and an audion tube means controlled by said oscillating circuit, receiving means responsive to said coded current and connected to shock excite said oscillating circuit, and decoding means energized only during oscillation oi said oscillating circuit, the decoding means changing its operative position for each separate current impulse.

In testimony whereof I atlix my signature.

WILLIAM D. HAILES.

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